function loadcmd = sample_loads_json(buses,LD_coffs)
    %LD_coffs——负荷缩放系数，同buses的行数一样长度的向量
    if ~exist("LD_coffs","var")
        LD_coffs=ones(height(buses),1);
    end
    idx = buses.Pd>0 | buses.Qd>0;
    LD_coffs=LD_coffs(idx);
    loadcmd= compose("%s|%.3f|%.3f",buses.bus(idx),buses.Pd(idx).*LD_coffs,buses.Qd(idx).*LD_coffs);
    loadcmd=["node load table is as follows: Bus|Pd|Qd";loadcmd];
end